white dust?

[ickmagnet]

Something is not right with my tank.

After 2 years of everything running smoothly, I've had 3 fish die on me in the last month. Two jumped out of the tank and the third (my precious powder blue), just stopped swimming one day.

I've checked the Nitrite, Nitrate, PH, and Ammonia and everything seems fine.

The only thing "wrong" I can think of is that I do have a lot of aiptasia.

I was taking a look ay my fish today and noticed that all of them are covered in a pwodery white dust, like they are covered in sand or something. I know what ick looks like and it is definitely not that.

They do appear to be eating fine. Any ideas?